Adjustable dual condenser



A ril 18 1939' K' JOHNSON ^DJUSTABLE DUAL GONDENSER Fi1ed Nov 6 1957Patened Apr. 18, 1939 UNITED STATES PATENT OFFICE A)]USTABLE DUAINDENSER An object of this invention is to provide a dua condenser of theadjustable type in which there is a single adjusting !nenlber, as ascrew, Which iS S0 0peratively related to the condenser ele- Inents thatInovelnent of the nernber vanes in equal degree the ca^pacities of thetwo units of the dual condenser So tha(t the tw0 capacities aresubstantiay equal at al postions of adjust!nent.

Another object is to inprove generaly condensers of t1is type.

I'l1ese and other objects, as will hereina.fter appear, areacco!np]ished by this invention, vvhich is fully described in thefolowing specincation and Shown in the acc0!npanying drawing, in wllichl'ig. 2 is a rear elevation of the Same;

Iig. 3 is an enlarged section on the line 3 0f 'ig. 1;

1'ig. is 8 partia^l transverse section on the line 44 of 1:ig 3;

l'ig 5 is an eleva(tn of one of the pla'tes of the condenser; and

The embodiment iuustrated comprises a metal mounting plate or franeWhich for convenience in mounting may have a ledge and a foot l 2 thelatter preferably being provided with two or Inore holes l3 by nleans ofvvhich the plate my be mounted.

Two pairs Of spaced insulating strips pass through the plate ll and arefirInly set at four spaced p0ints tllerein, as shown in l 'igs. 1 and 3for each condenser( These serve as guides for both the plates and thedielectric spacers as will presently be Seen Insulating spacers |5, |5are placed on each side of the Inounting plate, and these have notchesIG (Eig] 6) vvhich overlie 0 the insulating strips s0 as to bep0sitioned thereby.

outer or negative pa'tes IT ('ig 5) are p1-0vided which have slottedopenings l8 at one end by means of which they nt over the guides 'leyare guided a't the opposite end by Ineans of tongues ls which passbetvveen the guides l and a're positioned against endvvise xnovement byshoulders 2@ vvhich engage the in ner sides 0f the gmdes P0sitive plates2|, 22 Similar to the pla'te are then inserted, but their terr!inasextend in the opp0site` direction With a negative plate 23 a]1 theseplates being separated by dielectric spacers 25 similal ;0 the Spacers AScrew 2G pases through the plate and is provided With a Single pitchthread 2 st the 6, 1937, Serial N0. l73,z32

left hand end which is threaded through a' hole in the plate lu having asingle pitch threa,d. A lock nut 2- is adjustably Set on the threadedportion 26 and has al washer 28 between tlis nut and the outer plate 22.

The opposite end of the screw is provided with a double pitch thread 2wmch is threaded through a nut 2 which is secured as by brazing t0 theouter late 2z 'I'11e screw Inary be turned by any convenient neans (notshown) Such as a shaft with a tongue in the slot 26- 'I'l11s, bycarefully adjusting t`he nut 27 While the screw 2 is held, the capacityof the w0 condenser units n1ay be rendered Substantia]ly equanl. 'I'llenany rotary nloven1ent of the screw 26 Will Inove the nuts 2T, 29 towardor from the franle l| in equa amounts, and since the tvv0 condenSers areInade substantia1 duplicates, the ca pacities reInain substantially equlfor aJl Settings. ''1is permits these condensers to be used in two tunedstages of a radio receiving set so that when the tuning is done even byan inex perienced operator the tvv0 stages will be sub- Stantially inresonance for all positions of the screw 2` 1. In a dual condenser, Bnlounting plate, substantially identical condenser units having reSilient plates disposed on each side of Said Inounting plate, and aScrew passing through said u11its and screwed through an opening in thenountng plate and operably connected to Said units for Si!111ltae0uslyvarying the pressure exerted on the two condenser units equa1ly S0 thatthe capacities of the tvv0 condensers re!na.in subst ntia 1ly equal foral settings 2. In a dual condenser, a Inounting plate, substantiauyidentical condenser units having resilient plates disposed on each sideof said mounting plate, and n1eans for varying the pressure exerted onthe two condenser units e uall so that the capacities of the tw0condensers renlain Substantially equa1 for all settings, said Ineansincluding a screw passing through both condensers a'!1d through themounting pla'te, al portion of the screw threaded through the n1ountingplate and Secured to a nut on one condenser unit nd ha'ving a' thread ofa given pitch vl'ile the portlon of the screw threaded through nutnonrotata.bly mounted on the 0ther unit has twice the pitch of thefirst-Tlentioned` portion Whereby ai r0tary movement of the screw movesthe tw0 nuts toward or from the Inounting pa'te in equall amounts

